Add : \( \frac{1}{2} \) + \( \frac{1}{6} \) + \( \frac{1}{12} \) + \( \frac{1}{20} \) + \( \frac{1}{30} \) + \( \frac{1}{42} \)
\( \frac{19}{21} \)
\( \frac{6}{17} \)
\( \frac{5}{7} \)
\( \frac{16}{21} \)
Count the number of triangles in the figure.
Choose the mirror image for the following figure.